汞和两种农药复合污染对土壤转化酶活性的影响

 通过模拟方法研究了豆磺隆,呋喃丹2种农药与重金属汞(Hg)单一及复合污染对草甸棕壤和黑土4个土壤转化酶活性的影响.结果显示,在试验浓度范围内,土壤添加豆磺隆和呋喃丹后,转化酶变化幅度分别为-12%～7%和-6%～7%,表明2种农药对土壤转化酶的毒性较小;Hg对转化酶最大抑制率为22%～35%,二者之间呈显著的对数负相关关系,表明Hg对转化酶的毒性较大,转化酶在一定程度上可作为Hg污染的监测指标,通过对数方程计算出4个土样的生态剂量(ED₅₀)分别为76.68,727.49,236.52,316.59mg/kg;Hg和2种农药之间普遍存在交互作用,豆磺隆与Hg复合污染引起土壤转化酶最大净变化量(△I)为对照的-12%～15%,呋喃丹和Hg为-25%～-6%,有机质对复合污染产生的毒性有明显的缓冲作用.

Influence of joint pollution of mercury and two kinds of pesticides on invertase activity in soils

Through simulative methods, the influence on the soil invertase activity of 4 soils of grassy marchland brown and black soils by the single and joint pollution of 2 kinds of pesticide chlorimuron-ethyl, furadan and heavy metal mercury was studied. In the range of test concentration, the varying extents of invertase were -12%~7%, -6%~7% respectively after addition of chlorimuron-ethyl and furadan into the soil, showing that the toxicity of two pesticides was small relatively; the maximum inhibition rate on invertase by Hg was 22%~35% showing market negative correlation between invertase activity and Hg contamination. Hg has higher toxicity on invertase; invertase activity could be definite degree a monitoring index of Hg contamination. The ecological doses (ED50) of 4 soil samples were 76.68, 727.49, 236.52 and 316.59mg/kg respectively. There existed generally mutual action between Hg and two kinds of pesticides. The joint pollution of chlorimuron-ethyl and Hg induced the greatest net varying amounts (?I) of soil invertase were -12%~15% of the contrast and -25%~6% for furadan and Hg. Organic substance had obvious buffering action on the toxicity produced by joint pollution.